Mini-incision surgery for total knee replacement - Interventional Procedures Consultation Document

NATIONAL INSTITUTE FOR HEALTH AND CLINICAL EXCELLENCE

Interventional procedure consultation document

Mini-incision surgery for total knee replacement

Mini-incision (also known as ’minimally invasive’) surgery for total knee replacement is a possible alternative to standard total knee replacement for people with a worn, painful knee joint (usually because of ’wear and tear’ arthritis). The procedure involves removing the damaged surfaces of the knee joint and putting in a replacement knee. A small cut is made over the knee and specially designed equipment is used to gain access to the bones. This means that the knee cap does not need to be temporarily moved to one side.

The National Institute for Health and Clinical Excellence (NICE) is examining mini-incision surgery for total knee replacement and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. NICE’s Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisers, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about mini-incision surgery for total knee replacement

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

  • comments on the provisional recommendations
  • the identification of factual inaccuracies
  • additional relevant evidence, with bibliographic references where possible.

Note that this document is not NICE’s formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that NICE will follow after the consultation period ends is as follows.

  • The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
  • The Advisory Committee will then prepare draft guidance which will be the basis for NICE’s guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

For further details, see the Interventional Procedures Programme manual, which is available from the NICE website (www.nice.org.uk/ipprogrammemanual).

NICE is committed to promoting through its guidance race and disability equality and equality between men and women, and to eliminating all forms of discrimination. One of the ways we do this is by trying to involve as wide a range of people and interest groups as possible in the development of our guidance on interventional procedures. In particular, we aim to encourage people and organisations from groups in the population who might not normally comment on our guidance to do so. We also ask consultees to highlight any ways in which draft guidance fails to promote equality or tackle discrimination and give suggestions for how it might be improved. NICE reserves the right to summarise and edit comments received during consultations, or not to publish them at all, where in the reasonable opinion of NICE, the comments are voluminous, publication would be unlawful or publication would otherwise be inappropriate.

Closing date for comments: 24 February 2010

Target date for publication of guidance: May 2010

 

1       Provisional recommendations

1.1  Current evidence on the safety and efficacy of mini-incision surgery for total knee replacement is adequate to support the use of this procedure provided that normal arrangements are in place for clinical governance, consent and audit.

1.2  Mini-incision surgery for total knee replacement should only be carried out by surgeons with specific training in the procedure.

1.3  Surgeons should submit details on all patients undergoing mini-incision surgery for total knee replacement to the National Joint Register (www.njrcentre.org.uk).

2       The procedure

2.1    Indications and current treatments

2.1.1  The most common indication for a total knee replacement is symptomatic degenerative arthritis (osteoarthritis) of the knee joint.

2.1.2  Conservative treatments for arthritis include medications for pain and inflammation, and physical therapies. Corticosteroids may be injected into the knee joint to relieve inflammation. If these therapies are insufficient, a partial or total knee replacement may be necessary.

2.2    Outline of the procedure

2.2.1  The aim of mini-incision surgery is to reduce the length of incision and avoid eversion of the patella or dislocation of the knee joint. Instruments that enable the surgeon to work through a small incision and minimise the cutting of muscles are used to remove the surfaces of the tibia and femur. The same types of joint prostheses are used in mini-incision procedures as in standard knee replacement. Computer-guided navigation may be used to improve placement of the prostheses.

Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview, available at www.nice.org.uk/ip247aoverview

 

2.3    Efficacy

2.3.1  A randomised controlled trial (RCT) of 108 patients treated by computer-assisted mini-incision (n = 52) or conventional knee replacement (n = 56) reported that 34 patients from each group were pain free at 6-month follow-up (denominator not stated) (p = 0.15).

2.3.2  A non-randomised controlled trial of 200 knees reported that mean pain score (using a 10-point visual analogue scale; high score indicates worse pain) was significantly better in the mini-incision group (3.2 points) than in the conventional surgery group (3.8 points) at 1-year follow-up (p < 0.01).

2.3.3  The RCT of 108 patients treated by mini-incision or conventional knee replacement reported a non-significant difference in mean Knee Society knee scores (on a scale from 0 to 100; high score indicates less pain and better functional mobility) of 84 points and 85 points respectively at 6-month follow-up (p = 0.06). An RCT of 90 patients treated by mini-incision, computer-assisted mini-incision or conventional surgery reported mean knee scores of 83 points, 87 points and 86 points respectively at 12-week follow–up (p > 0.05).

2.3.4  An RCT of 80 patients treated by mini-incision or conventional surgery reported mean knee scores of 81 points and 77 points respectively at 12-week follow-up (p = 0.12).

2.3.5  A non-randomised controlled study of 747 knees reported that flexion was significantly greater in knees treated by mini-incision surgery (124°) than following conventional surgery (113°) at 24-week follow-up (p < 0.001).

2.3.6  The Specialist Advisers listed key efficacy outcomes as faster recovery, functional long-term outcome and implant survival at 10 years.

2.4    Safety

2.4.1  Non-randomised controlled studies of 200 and 137 patients reported myocardial infarction in 1% (1/90) and 1% (1/68) of patients treated by mini-incision surgery and in 0% (0/84) and 0% (0/61) of patients treated by conventional surgery (no deaths were reported).

2.4.2  Tibial component failure (requiring revision) was reported in <1% (2/725) of patients treated by mini-incision surgery in a non-randomised controlled trial of 732 patients (>12-month follow-up).

2.4.3  In a non-randomised controlled study of 137 knees, patella tendon shortening of >5% occurred in significantly more knees treated by conventional surgery (37% [21/57]) than in knees treated by mini-incision surgery (12% [9/74]) at 2-year follow-up (p = 0.001).

2.4.4  A non-randomised controlled study of 747 knees reported that ‘patella clunk’ occurred significantly more frequently following mini-incision surgery (6% [17/275] of knees) than following conventional surgery using the same prosthesis (<1% [1/222] of knees) at 1-year follow-up (p < 0.001).

2.4.5  In the non-randomised controlled study of 137 patients, secondary manipulations for reduced range of movement at 6 weeks were reported in 3% (2/68) of patients treated by mini-incision surgery and 7% (4/61) of patients treated by conventional surgery.

2.4.6  In the RCT of 80 patients treated by mini-incision or conventional surgery, deep vein thrombosis requiring prolonged anti-coagulation was reported in 0% (0/40) and 3% (1/40) of patients respectively (12-week follow-up).

2.4.7  Deep wound infection requiring 2-stage revision surgery and draining haemarthrosis requiring evacuation were reported in <1% (2/725 and 1/725 respectively) of knees treated by mini-incision surgery in the non-randomised controlled study of 732 knees. Deep infection requiring 2-stage reimplantation was reported in 1% (2/335) of patients in a case series of 335 patients at a median 2-year follow-up.

2.4.8  The Specialist Advisers listed anecdotal or published adverse events as damage to skin and soft tissue, increased operative time and malpositioning of implant. They considered theoretical adverse events to include inadequate removal of bone cement, nerve damage and damage to blood vessels.

2.5    Other comments

2.5.1  The Committee noted that there is no generally accepted definition of a ’mini-incision’ approach to knee replacement.

3     Further information

3.1  For related NICE guidance see www.nice.org.uk.

Bruce Campbell
Chairman, Interventional Procedures Advisory Committee
January 2010

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 It is the responsibility of consultees to accurately cite academic work in order that they can be validated.

This page was last updated: 24 May 2010